1. Field of the Invention
The present invention relates to a pneumatic tool, and more particularly to a pneumatic motor and a pneumatic valve.
2. Description of Related Art
A conventional pneumatic motor is mounted in a pneumatic tool and is rotated by compression air for driving the pneumatic tool to do repeating mechanical operations, such as rotation or movement.
With reference to FIG. 9, a conventional pneumatic motor 70 includes a housing 71, which accommodates a rotor 72, a pneumatic valve 73, and an air-supply unit 74 in sequence.
With further reference to FIGS. 10 and 11, the pneumatic valve 73 includes an air flowing unit 731 and an adjusting gate 732. The air flowing unit 731 is disk-shaped and has a back, a front and a center. A fixing hole 7311 is formed in the back of the air flowing unit 731 through the center. Two air-flowing openings 7312 are curved and are formed in the air flowing unit 731 and are located above the fixing hole 7311. Two air-flowing passages 7313 are formed in the front of the air flowing unit 731. Each air-flowing passage 7313 is connected to one of the air-flowing openings 7312.
The adjusting gate 732 rotatably abuts against the back of the air flowing unit 731 and has a back, a front and a top. An air-in passage 7321 is L-shaped and is formed from the back to the top of the adjusting gate 732. An air outlet 7322 is formed in the front of the adjusting gate 732 and communicates with the air-in passage 7321.
With reference FIGS. 9 to 11, when the air-supply unit 74 leads compressed air into the housing 71, the compressed air will flow into the adjusting gate 732. The adjusting gate 732 is able to rotate and switch positions for communicating one of the air-flowing openings 7312 with the air outlet 7322. The compressed air is able to flow out of the air-flowing passage 7313 via the air outlet 7322 and the air-flowing opening 7312 and to drive the rotor 72 to rotate. The other non-in-use air-flowing opening 7312 of the air flowing unit 731 is able to release part of the compressed air to prevent the back pressure from generating inside the housing 71 and to keep the rotation of the rotor 72 smooth.
The compressed air will flow up to hit the inner surface of the air-in passage 7321 when the compressed air flows out from the air outlet 7322 via the L-shaped air-in passage 7321. The adjusting gate 732 will be pushed backward in the horizontal direction of the compressed air and cannot abut against the air flowing unit 731 closely. Therefore, a gap will be formed between the adjusting gate 732 and the air flowing unit 731, and part of the compressed air will flow out from the gap. Thus, the compressed air cannot flow into the air flowing unit 731 completely and will decrease the speed of the rotor 72.
To overcome the shortcomings of the conventional pneumatic motor, the present invention provides a pneumatic motor and a pneumatic valve to mitigate or obviate the aforementioned problems.